The Flow Cytometry Facility at Beckman Research Institute of the City of Hope has been in operation since 1979. Use of the facility has broadened during that time to now include 6 user groups representing all major clinical and research departments with annual use approaching 1200 billed hours. The major user groups have 14 peer reviewed funded PHS grants and an equal number pending. The instrument was the first FACS IV machine delivered in the United States and it lacks a number of capabilities now available on the FACS 400 series including (1) flow cytometry specific software, (2) log amplifier, (3) 90 degree scatter (third PMT), (4) pulse processing electronics and optics, (5) automatic sampler and {6) single cell deposition. Funds are requested to update the instrument in this successful facility.